In a variety of medical procedures various fluids may be added to or removed from the circulatory or other physiological systems of a patient. For example, a number of blood filtration and extra-renal replacement therapies remove and filter blood and other fluids from the circulatory or renal systems of a patient and return treated fluids or replacement fluids to the patient. For example, therapies based on haemofiltration, haemodialysis, haemodiafiltration, and plasmatheresis remove and replace a quantity of fluids from a patient. During these procedures, the quantity of fluids removed from and delivered to the patients must be closely monitored. For example, the delivery of a greater amount of fluid to the patient than was removed may result in unnecessary organ strain or, in the case of blood therapies, high blood pressure. In contrast, the delivery of a lesser amount of fluid to the patient than was removed may result in low blood pressure, dehydration, organ failure, or a host of other related medical complications.
A number of fluid replacement devices which incorporate one or more scales configured to control flow pumps and to regulate the delivery of fluids to and from a patient have been developed. Typically, these systems utilize a first weight scale to weigh the amount of fluid being removed from a patient and a second weight scale to weigh the amount of fluid being delivered to the patient simultaneously. While these systems have proven successful in the past, a number of shortcomings have been identified. For example, multiple scale systems are complex devices which have been proven difficult and time-consuming to calibrate. In addition, systems utilizing multiple scales require an operator to precisely monitor multiple weighting systems whose measurements are constantly changing during a particular procedure.
In response, alternate systems utilizing a single weight scale have been developed. These single scale systems measure and balance the quantity of fluid removed from and delivered to the patient simultaneously. Typically, a container support device having multiple container supports thereon is coupled to the weight scale. An empty container for receiving fluid from the patient and a container having delivery fluids therein are positioned on and essentially balanced on the container support device. Thereafter, supply lines are coupled to each container and pumps, usually peristaltic pumps, are coupled to the supply lines. During use, the pumps remove fluid from and deliver fluid to the patient simultaneously. Ideally, at all times during the procedure combined weight of the two containers remains substantially constant. The weight scale having the container support device coupled thereto constantly monitors the combined weight of the two containers during the procedure. During use, should the combined weight of the two containers vary beyond a predetermined limit an alarm will be triggered and the pumps connected to the containers will cease operation. In contrast to multiple scale systems, single scale systems are easier to operate and require considerably less time to calibrate than multiple scale systems. However, at least one shortcoming associated with both systems stems from inaccuracies in the weighting process. Torque or tortional constraints present within the weighting systems may affect weight measurement accuracy. In addition, balancing and calibrating present systems is a time consuming and labor intensive process. Furthermore, the ability of present systems to support multiple delivery containers (e.g. 3 or more containers) has proven problematic. More specifically, monitoring and balancing one container for receiving fluid from the patient and one container for delivering replacement fluids to the patient has been accomplished with some success. However, monitoring and balancing one container for receiving fluid from the patient and multiple containers for delivering replacement fluids to the patient has proven to be more problematic.
Thus, in light of the foregoing, there is an ongoing need for a container support system adapted to couple to a material weighting device and capable of supporting and balancing multiple containers during a medical procedure.